Official Power
Southwestern US hydropower hits lows amid persistent drought
Prolonged drought in the Colorado River Basin has reduced Southwestern US hydropower generation to record lows, according to the US Energy Information Administration.
Key points
- Hydropower generation from April through August fell 19% year-on-year.
- Water levels at Lake Powell and Lake Mead dropped near minimum power pools.
- Federal authorities mandated water consumption cuts across three states.
What happened
Prolonged drought conditions across the Colorado River Basin have forced hydroelectric generation down to record low levels in the Southwestern United States, according to data from the US Energy Information Administration (EIA). The affected electricity supply region covers Arizona, New Mexico, and parts of Nevada and California.
Between April and August, generation dropped 19% compared to the same period in the previous year, and fell 28% below the 10-year average. Major reservoirs including Lake Powell and Lake Mead recorded critically low water elevations. Lake Powell reached just under 1% above its minimum power pool threshold at the end of September, while Lake Mead stood 9% above its required minimum level.
To manage the dwindling reserves, the US Bureau of Reclamation altered water releases from upstream reservoirs such as Flaming Gorge and reduced outflows from Lake Powell. Simultaneously, the Department of the Interior instructed California, Arizona, and Nevada to curtail their collective annual water consumption by 1.25 million acre-feet over the next two years to protect downstream generation potential at the Hoover Dam.
What comes next
The EIA projects total Southwestern hydropower generation to reach 6.13 billion kilowatthours in 2026, marking a 9% decline from the prior year. Output is anticipated to remain subdued at 6.1 billion kilowatthours through 2027. While anticipated precipitation from seasonal weather patterns could offer temporary relief, multiple years of severe water scarcity mean that a single wet season is unlikely to fully reverse the deficit.
Why it matters
The crisis in the Southwestern United States highlights the vulnerability of regional power grids heavily reliant on hydroelectric assets during prolonged dry spells. For energy investors and policymakers in developing regions, the situation underscores the importance of diversifying power generation mixes to insulate grids against climate shocks. Globally, renewable energy portfolios must balance hydroelectric reliance with alternative generation sources to maintain stability when water availability fluctuates. According to World Bank figures from 2021, the global renewable share of electricity output stood at 27.8 percent, illustrating the diverse mix required to secure reliable energy supplies worldwide.
Original reporting
This article draws on the following reports. Read them in full on the publishers’ sites.
Context from CEII
Grids decide whether generation becomes power that homes and businesses can rely on. Generation mix, transmission and distribution losses, and tariffs together shape reliability and the case for investment.
91.9% of people worldwide had electricity in 2024Countries in this story
Written by the CEII Desk, the Centre’s automated newsroom, from the reporting credited above and CEII’s own data. Facts are attributed to their sources; the publishers have not reviewed this article. Spotted an error? Tell our editors.
